Dry kiln



M. C. WARREN AND 1 1. KROHN.

DRY KILN.

APPLICATION FILED Nov. 3o. I92I.

1943594@ Patented NOV. 7, i922.

l 2 SHEETS-SHEET WKZ I II M IIIAI II III II M. C. WARREN AND 1. KHOHN.

DRYKILN. APPLICATION FILED NOV. 30. 192|. 1,435,094. PantedNov. 7,1922, 2 SHEETS-SHEET 2.

$1 LA! n u n n g! -m N l -..Q NL QQ Y w w N W my. `f

L ii n u n -N .1l

i 'Y 1 b. Q i N *i l @e N i I N r I f Q N i Il Ilm Il ll Il Ilm Il TENT MURREIJL C. WARREN AND JULIUS J'. KROHN, OF ARCATA, CALIFORNIA, ASSIGNORS TO CALIFORNIA BARREL CO., OF SAN FRANCISCO, CALIFORNIA, A CORPORATION' OF CALIFORNIA.

DRY KILN.

Application filed November 30, 1921. Serial No. 518,928.

To @ZZ lwi om t 'may concern.'

Be it known that we, MURRELL C. TAR- nnN and JULiUs J. Knorin, citizens ot the United States, residing at Arcata. in the county oit Humboldt and State of California, have inventedcertain new and useful Improvements in Dry Kilns, of which the.

following is a specication.

Our present invention relates to an improvement in dry kilns and in the provision of a kiln adapted for uniformly drying staves, heading, boxV shooks7 lumber or any product by reversing the natural draft or circulation ot hot air through the stock dui'- i'ng the drying period.

One of the principal objects olf this invention is to provide a kiln equipped with an arrangement of grouped heating elements and battles,y so disposed as to enable the circulation ot' heated air in its direction ol. travel through thestock to be changed at will by a variation in the temperature of the grouped hea-ting elements or their position relative to the material to be dried, without the aid of artitficial dra'tt means. To provide a construction wherein the drying operation is performed by a natural drai't of heated air and one which is capable of operating to dry the stock uniformly throughout the charge.

l'Vith the above mentioned and other objects in view, the invention consists in the .novel construction and combination of parts hereinafter described, illustrated in the acci'iinpanying drawings and pointed out in the claims hereto appended; it being understood that various changes in the iorni, proportion, size and. minor details oi construction within the scope of the claims may be resorted to without departing from the spirit or sacrificing any of the advantages ot the invention.

in the embodiment of the invention illustrated- F 1 is a transverse sectional view through a progressive kiln, taken on line 1-1 ot Fig. e, illustrating the downward circulation of air through the stock.

Fig. 2 is a view similar to Fig. l, taken on line 2-2 of Fig. 4L, with the circulation ot the air upwardly through the stock.

i? 3 is a longitudinal sectional view horizontally through the kilnj taken on line 3 3 of Fig. 4, disclosing the grouping of the heating elements.

F ig. et is a vertical sectional view taken on line 1`t of Fig. 3, disclosing the connection for the grouped heating elements.

In the drawings, wherein like characters of reference designate corresponding parts- 1 indicates the kiln housing preferably rectangular in plan and longitudinallv through which extend tracks 2 raised or elevated from the bottom 3 thereof and supported preferably on girders -;lresting on piers 5. The tracks 2 extend from the kiln charge end 6 in pairs longitudinally through the saine to the discharge end l7. and the openings 8 in opposite ends of the kiln through which said tracks extend are adapted to be closed by doors or other suitable mechanism, not shown, to provide a closing chamber within the kiln housing 1. Y

Transversely across the bottom of the housing` l below tracks 2 and positioned aboutinidway of the length of the housing is a suitable outlet duct 9, which communicates with 'a vertical portion or outlet stack 10. Extending longitudinaly within the kiln and one paralleling the outer edge of each track 2 are the baii'les l1, each extending from the bottoni 3 of the housing to a point slightly above the upper edge of the tracks 2.

It will be observed in Figs. 1 and 2 that the baffles 11 parallel each pair of tracks 2 at their outer sides and provide walls toi' separating adjacent pairs oit tracks providing between them. dues The battles 'tor substantially their tull length are provided :it their lower edges with vents ,l which connect the base of tlues 12 with the chaml'iers 14e formed by the baiiles beneath each pai: of tracks 2.

Grouped in the lines 12 between adjacent pairs of tracks 2 at the charge end ot the kiln and extending preferably to a point slightly beyond the duct 9 are the heating elements 15 preferably in the form of steam pipes connected with a header 16 and draining into a drain 17 connected with a trap 18. The pipes 15 are adapted to cause a circulation of air upwardly through the lues 12 between the charges ot material 16 on tracks 2 at the charge end ot the kiln and cause the same to circulate downwardly through the stock into the unoccupied chamber 121 beneath each pair of rails, maintaining this circulation through, the vents 13 solely by the temperature of said grouped pipes 15. This downward circulation of heated air through the stock, when the same is ted green into the charge end o1' the kiln, takes advantage of the natural tendency of air on cooling to descend and thus create a definite circulation in the direction of the arrows A, Fig. 1, without mechanical stimulation. This operation thoroughly heats the material and slowly dries out the iree moisture contained within the cells.

Between the pairs of rails 2 and cooperating pairs of baffles 11 in the chambers lf-t are grouped other heating pipes 18` prc'l era-bly supplied with steam from the header 19 and which drain into a member Q() connected with a trap 21, and said pipes are et a length extending approximately one-hair the length of the housing 1 and as will be observed by a comparison of Figs. 1 and 2 are of a greater number per unit or group than those positioned within the Hues 15, thereby creating a greater temperature at the discharge end oi' the kiln than at the charge or receiving end.

The stock as it progresses through the kiln moves over they groups of pipes 18 where it is subjected to a rising circulation of heated air passing upwardly from the chambers 14 through the stock in the direction oi' the arrows B-Fig Q oi the drawings, the intense rising heat moving by natural drait circulation upwardly through the chambers let, stacks 16 and downwardly through flues 12 and inwardly through rents 13 encounters little resistance in passing through the stocks, as the greater percentage o moisture has been removed from the material in the early stages of drying.

y this present apparatus, .which has been illustrated in connection with a progressive kiln, but which is equally as well adapted for use in a compartment kiln, the stock is uniformly dried by alternate natural circulation of heated air controlled solely by or the posit-ion of the stock relatively to certain groups of heating elements.

Fresh air is adapted to bev admitted at opposite sides of thekiln for its full length between the kil-n supporting members 1.

1. A dry kiln including a housing for receiving the material to be dried, a plurality ot grouped heating elementsl below the plane ot' the material, one group lying directly beneath the material and the other group lying on either side of the material, and a pair of vented baillesfor controlling circulation of heated air through said material.

2. A progressive kiln comprising a housing, means for directing the material to be dried therethrough, a group of heating elements lying beneath. the material at one point of its travel through the housing, a group of heating elements below the material on either side at another point ot' its 'travel through the housing, and a pair oi vented batiies at each side of the material between the planes of the groups of heating elementsI throughout the length of the kiln.

3. A kiln comprising a housing for receiving the material to be dried, a plurality oi groups ot`-independent heating elements lying beneath the material at its point with in the housing and on either side thereof, and a pair of vented ballies at each side of the material between the planes ot' the groups of heating elements.

In testimony` whereof we have signed our naines to this specification.

MURRELL- C. WARREN. JULUS J. KROHN. 

